I’m still using pfsense and considered switching over to opnsense but I found out it doesn’t have something similar to pfblocker.

I’ve been using Slackware since 1994, saw redhat and Debian being born.

Slackware has been around long before those distros appeared

Yes, that’s true and a bad or undersized power supply also but in my experience it is much more likely to have a bad disk than to have something else fail

I would check the kernel messages (sudo dmesg) and check for errors on the ata bus. If there are it’s most likely the disk that is failling